CN104105678A

CN104105678A - Process for producing DCB substrates

Info

Publication number: CN104105678A
Application number: CN201280069294.2A
Authority: CN
Inventors: J·舒尔兹-哈德尔; K·施米德特; K·埃克塞尔
Original assignee: Curamik Electronics GmbH
Current assignee: Curamik Electronics GmbH
Priority date: 2011-12-27
Filing date: 2012-12-27
Publication date: 2014-10-15
Also published as: DE102012101057A1; WO2013097845A1; EP2797853A1; US20140338162A1; KR20140119047A; JP2015503500A

Abstract

Process for producing DCB substrates having in each case at least one ceramic layer which consists essentially of aluminium nitride (AlN) and is provided on at least one surface side with an intermediate layer consisting essentially of aluminium oxide and also has at least one metallization formed by a metal layer or metal foil on the intermediate layer.

Description

For the preparation of the method for DCB-base material

The present invention relates to according to the preamble of claim 1 for the preparation of the method with the DCB-base material of the form of the printed circuit board (PCB) of circuit and/or module particularly.This method is known.

Known so-called " DCB-method " (directly copper crimp technology), described method is for example by being used metal sheet or tinsel, the metal sheet particularly being formed by copper or copper alloy or tinsel, thereby make metal level or metal sheet (for example copper coin or Copper Foil) be connected to each other and/or be connected with pottery or ceramic layer, described metal sheet or tinsel have the layer or the coating that are made up of the compound of metal and reactant gas (preferably oxygen) in its face side.In the method for describing at for example US-PS 37 44 120 or in DE-PS 23 19 854, described layer or coating form for example, eutectic melt (melting layer) lower than the melt temperature of metal (copper) of melt temperature together with adjacent metal, thereby therefore can, by applying paper tinsel and by heating all layers, it is connected to each other on pottery, particularly pass through substantially only molten metal or copper in the scope of melting layer or oxide skin.

Described DCB-method for example has following method steps:

So oxidized metal paper tinsel (for example Copper Foil), makes to form uniform metal oxide layer or copper oxide;

On ceramic layer, apply tinsel, for example Copper Foil;

Mixture is heated between approximately 1025 to 1083 DEG C, for example the process temperature of approximately 1071 DEG C;

Be cooled to room temperature.

Hereinafter referred to as " the DCB-base material " of base material that according to described method prepared by (below also referred to as " DCB-crimping "), no matter and the metal that metal level or tinsel are used how.

In the case of using the ceramic layer that form by aluminium nitride (AlN), thereby also knownly at least one face side of each ceramic layer, first pass through thermooxidizing in air or in oxygen-containing atmosphere and form the middle layer being formed by aluminum oxide (Al2O3).The tinsel (for example Copper Foil) that only just likely makes to form respective metal compound by DCB-crimping via described middle layer is connected with pottery.

The object of this invention is to provide a kind of method, use described method to prepare and there is better quality, particularly there is the DCB-base material with at least one ceramic layer substantially being formed by aluminium nitride of better machinery and/or electricity and/or thermal characteristics.In order to realize described object, the method claimed in claim 1 of giving chapter and verse.

The essential characteristic of the method according to this invention is, each the used ceramic layer substantially being formed by aluminium nitride (AlN), for example there is at least 90% aluminium nitride share, preferably there is at least 96% aluminium nitride share, wherein other component is especially sintering aid, for example yttrium oxide (Y2O3), calcium oxide (CaO), magnesium oxide (MgO) and for example boron nitride of releasing agent (BN) and for example garnet of reaction product (Y2O3'Al2O3) and boron oxide (B2O3), before forming at least one middle layer being formed by aluminum oxide (Al2O3), in relevant surfaces side, carry out machinery and/or chemical purification, remove the upper layer of the reaction product that caused by sintering process and that especially comprise sintering process existing in relevant surfaces side.

In evolutionary approach of the present invention, for example described method of following design,

Thereby for example mechanically remove scalping by brushing, polishing, polishing, sandblast, high pressure spraying, particularly comprise the upper layer of oxide ceramics,

And/or

By chemical treatment, for example, by with basic solution, be preferably greater than 10 by PH-value, thereby preferred PH-value is greater than 12 aqueous solution processing except scalping,

And/or

Treatment temp between 20 DEG C and 100 DEG C, preferably removes scalping in the temperature that is greater than 50 DEG C,

And/or

By with soda lye, preferably process with 5% soda lye and/or by with potassium hydroxide (KOH) and/or sodium carbonate (Na2CO3) thus process and remove scalping,

And/or

In liquid and/or steam, thereby for example by remove scalping in the Temperature Treatment up to 300 DEG C with hot mode in autoclave under pressure,

And/or

Before forming at least one middle layer, at least one face side of ceramic layer, apply the thin layer that forms or formed by least one other copper-containing compound by copper or cupric oxide, and form at least one middle layer by thermooxidizing afterwards,

And/or

The so long time is carried out in thermooxidizing, until the layer thickness of at least one middle layer (3) is adjusted between 0.5 μ m and 10 μ m,

And/or

It is overlapping or carry out successively in time in time at least in part for removing the machinery of at least one upper layer and chemical process,

And/or

By ceramic layer being immersed to the aqueous solution of copper ions, for example Cu++ ion content is 0.005 to 2.0Mol/l the aqueous solution, thereby applies the thin layer that is formed or be made up of at least one copper-containing compound by copper or cupric oxide,

And/or

Thereby deposit and/or apply by electroless plating by sputter and/or by CVD-the thin layer that forms or form or formed by least one other copper-containing compound by cupric oxide by copper,

And/or

By thermooxidizing, by the oxygen-containing atmosphere between 10% and 90%, ceramic layer is heated to the temperature between 800 DEG C and 1450 DEG C in air or in oxygen share, thereby form at least one middle layer,

And/or

Described method has following method steps:

In at least one face side of the ceramic layer through purifying being formed by AlN, apply the tinsel through oxidation that at least one is made up of copper or copper alloy,

At least one tinsel and ceramic layer are heated to the temperature of 400 DEG C-1083 DEG C,

Remove at least one tinsel, preferably after cool metal paper tinsel and ceramic layer, remove,

Thereby in oxygen-containing atmosphere, in oxidation ceramic layer at least one face side at ceramic layer, form middle layer the temperature of 850 DEG C-1450 DEG C, and

At least one tinsel of DCB-crimping at least one face side of ceramic layer,

And/or

Described method has following method steps:

The ceramic layer through purifying being formed by AlN the temperature oxidation of 800 DEG C-1450 DEG C,

At least one tinsel being formed by copper or copper alloy of DCB-crimping at least one face side of the ceramic layer through oxidation,

Remove at least one tinsel, preferably remove by etching,

At the temperature of 800 DEG C-1450 DEG C oxidation ceramic layer (2) again, and

At least one tinsel of DCB-crimping at least one face side of ceramic layer,

And/or

Described method has following method steps:

Form undressed paper tinsel by casting and/or rolling and/or suppress by aluminium nitride and sintering aid, and prepare former base ceramic layer by sintering by described undressed paper tinsel, in at least one face side of ceramic layer, form middle layer, then make to be connected with described middle layer through metal level or the tinsel of preoxidation by DCB-crimping, form at least one middle layer in the relevant surfaces side of ceramic layer before, remove the upper layer being caused by sintering process existing in the relevant surfaces side of ceramic layer, then form middle layer

Wherein above-mentioned feature can be used separately or arbitrary combination use separately.

Within the scope of the invention, statement " substantially " or " approximately " means than each exact value +/-10%, preferably the deviation of +/-5% and/or for function the deviation of the form of unessential variation.

By the following description of embodiment and draw evolutionary approach of the present invention, advantage and application possibility by accompanying drawing.At this, feature all descriptions and/or that show in accompanying drawing mode forms basic theme of the present invention individually or with arbitrary combination, no matter and its summary in the claims or its how quote.The content of claim is also considered to the integral part of specification sheets.

Accompanying drawing by embodiment is explained the present invention in more detail.

Fig. 1 has shown the cross-sectional view of the DCB-base material with the insulation layer that is made up of aluminium nitride (AlN) or ceramic layer;

Fig. 2 situation a)-shown the different methods step for the preparation of the DCB-base material of Fig. 1 in f);

Fig. 3 has shown that the ceramic layer being made up of aluminium nitride in the method for Fig. 2 is together with the enlarged view that is applied in the middle layer being substantially made up of aluminum oxide (Al2O3) on described ceramic layer;

Fig. 4 situation a)-shown in another embodiment of the invention the different methods step for the preparation of the DCB-base material of Fig. 1 in f);

Fig. 5 has shown that the ceramic layer being made up of aluminium nitride in the method for Fig. 4 is together with the enlarged view that is applied in the middle layer being substantially made up of aluminum oxide (Al2O3) on described ceramic layer.

In Fig. 1; 1 is metal-ceramic-base material or DCB-base material; described base material is made up of ceramic layer 2, protective layer or middle layer 3 and metallide 4 and 5 substantially; described protective layer or middle layer 3 are positioned in each face side of ceramic layer 2, and described metallide 4 and 5 is applied on middle layer 3 separately and metallide 3 is configured for and forms the such as metallic region 3.1 of the form of lead wire of conductor, contact surface, mounting face etc.

Specifically, ceramic layer 2 is the ceramic layer being made up of aluminium nitride (AlN), for example there is aluminium nitride (AlN) share of at least 90 % by weight, preferably there is aluminium nitride (AlN) content of approximately 96 % by weight, wherein remainder is respectively other additive or is essentially other additive, particularly sintering aid, such as yttrium oxide (Y2O3), calcium oxide (CaO), barium oxide (B2O3), nitrogenize barium (BN), calcium oxide (CaO) etc.

Middle layer 3 is similarly ceramic layer and is made up of aluminum oxide (Al3O2), there is other component of low share, particularly sintering aid, for example, have yttrium oxide (Y2O3), nitrogenize barium (BN), barium oxide (B2O3), the calcium oxide (CaO) of low share.Layer or the paper tinsel of metallide 4 and 5 for forming by copper, by copper alloy or by aluminium or by aluminium alloy.

In Fig. 2 situation a)-shown the basic methods step for the preparation of base material 1 in f).

According to situation a), first by casting and/or rolling and/or suppress the undressed paper tinsel 2.1 and the sintering aid that are formed by aluminium nitride (AlN), then pass through in required sintering temperature, the each undressed paper tinsel 2.1 of for example the temperature sintering between 1600 DEG C and 1900 DEG C and other undressed stack of foils, thus the ceramic layer 2 being formed by aluminium nitride prepared.After sintering, obtain corresponding to situation former base ceramic layer 2.2 (fired ceramic layer) b).In the time of stacking sintering, use for example boron nitride of releasing agent (BN).This former base ceramic layer 2.2 has the upper layer 6 being caused by sintering process especially, and described upper layer 6 for example has the thickness between 0.05mm and 0.3mm.Upper layer 6 forms by impurity and by composition or the compound of sintering aid and releasing agent substantially, such as boron oxide (B2O3), boron nitride (BN), yttrium oxide (Y2O3), garnet (Y2O3'Al2O3), calcium oxide (CaO) etc.

According to situation c), in next method steps, except scalping 6, purify or the ceramic layer 2 of clean face side thereby obtain to have.

According to situation d), in next method steps, for example apply middle layer 3 by thermooxidizing.For this reason, in air or in oxygen-containing atmosphere, for example, such as, in the atmosphere that comprises the oxygen that rare gas element (nitrogen, argon gas etc.) and share are 10%-90%, ceramic layer 2 is heated to the temperature between 800 DEG C to 11450 DEG C.Middle layer 3 comprises composition (3.1) or the reaction product of sintering aid, such as Y2O3, BN, B2O3 etc. (Fig. 3 and 5) equally.

In another method steps, according to situation e), form metallide 4 and be connected with 5 the metal level forming by copper, by copper alloy, by aluminium or by aluminium alloy or DCB-crimping or the plane of tinsel.For this reason, the metal level through preoxidation or tinsel are applied to respectively on middle layer 3 and are then connected with middle layer 3 by DCB-crimping, and be connected with ceramic layer 2 by middle layer 3.Under the shielding gas atmosphere or inert gas atmosphere with low oxygen share; thereby carry out DCB-crimping by the DCB-temperature that the arrangement being formed by tinsel or metal level and ceramic layer 2 and middle layer 3 is heated between 1025 DEG C and 1083 DEG C, be then cooled to envrionment temperature.At this, each cupric oxide or aluminum oxide and adjacent copper or aluminium form eutectic melt, after being cooled to lower than DCB-temperature, by described eutectic melt, the metal level or the tinsel that form each metallide 4 or 5 are connected with adjacent middle layer 3, and are also connected with ceramic layer 2 by adjacent middle layer 3.Realize for this connection necessary pottery by middle layer 3 moistening by liquid eutectic melt, therefore just likely carry out metallide 4 and 5 or form the metal level of this metallide or the DCB-crimping of tinsel.

In another method steps, according to situation f), thereby form by using suitable with known covering method and engraving method to carry out at least structurizing of metallide 4 metallic region 4.1 that also electricity separates each other afterwards.When metallide 4 and 5 and particularly metallide 4 is structured be applied on the ceramic layer 2 that is provided with middle layer 3 during by DCB-crimping in advance at this, can omit this structurizing.

In order to remove scalping 6, can use different methods, particularly mechanical treatment and/or processing and/or the chemical treatment of removing material, for example use the suitable aqueous solution or alkali lye, preferably be greater than 10 or be preferably greater than the chemical treatment of 12 alkaline aqueous solution by PH-value, for example, by former base ceramic layer 2.2 is immersed to this aqueous solution or alkali lye.

At this, be suitable as the particularly soda lye (NaOH) for the treatment of soln, at this soda lye of 5% particularly.Other alkaline processing soln, for example KOH, the Na2CO3 in addition that are applicable to processing.At this, the preferably temperature between 20 DEG C and 100 DEG C, preferably processes in the temperature that is greater than 50 DEG C.Another kind of possibility is, processes with known solution under pressure in the autoclave up to 300 DEG C.Therefore the treatment time can be shortened greatly.

Except chemical treatment or replace chemical treatment, also can use the mechanical treatment except the material of scalping 6, for example by brushing and/or polishing and/or polishing, sandblast, high pressure spraying etc. except scalping 6.

In an embodiment of the method according to this invention, mechanical treatment carried out or carries out after chemical treatment before chemical treatment.In a preferred embodiment of the method according to this invention, mechanical treatment and chemical treatment overlapping carrying out in time at least in part.

Also find, when embed long-pending copper or cupric oxide or cupric ion in middle layer 3 time, adopt the method according to this invention can realize especially in metallide 4 and 5 and the ceramic good especially result being connected aspect quality or physical strength and electrical property.Same discovery, if do not embed copper or cupric oxide or cupric ion in middle layer 3, forms and is interrupted 7, and at described interruption 7 places, each middle layer 3 not exclusively forms or interrupts.

Described interruption 7 (i.e. particularly hole and interruption) causes and in the scope of being interrupted 7, between pottery and each metallide 4 or 5, does not produce DCB-connection, therefore below each metallide 4 and 5, forms bubble or cavity.Described bubble or cavity especially not only affect fatefully metallide 4 and 5 and pottery between the physical strength of connection, but also affect fatefully especially the dielectric strength of the base material 1 between metallide 4 and 5.Effectively avoid being interrupted 7 and relative shortcoming (Fig. 5) by embed copper or cupric oxide or cupric ion in middle layer 3.

Can embed by different way copper, cupric oxide or cupric ion.Fig. 4 has shown the basic step of described method in situation a-f, wherein preparing green ceramic 2.1, (situation a) afterwards, at sintering with purify former base pottery 2.2 (situation b and c) afterwards, in two face side of the ceramic layer 2 of (except scalping 6) through purifying, apply respectively the thin layer 8 that forms or formed by the compound that comprises copper by copper, as situation in Fig. 4 c) situation afterwards c) ' as shown in.Afterwards, again d) form and there are two middle layers 3 expecting thickness by thermooxidizing in oxygen-containing atmosphere according to situation.In described method, also middle layer 3 is adjusted to the layer thickness between 0.5 μ m and 10 μ m.

Other method steps (situation e) and f)) corresponding to as method described in conjunction with Figure 2.For example, with at 1.5x10 ^-4μ m and 1200x10 ^-4thickness between μ m carries out applying of layer 8.Can be for example by immersing in the aqueous solution of copper ions through the ceramic layer 2 purifying, for example Cu++ ion content is in 0.005 to 2.0Mol/l the aqueous solution, and/or deposits and/or electroless plating applied layer 8 by sputter and/or by CVD-.In the time that machinery removes scalping 6, also can there is by use the brush shapes stratification 8 of cupric bristle.

In the time of thermooxidizing in Al2O3 middle layer 3 another method of copper doped by the following method step carry out:

With aforesaid method purification pottery or ceramic layer 2,

On ceramic layer 2, apply the Copper Foil through oxidation,

In DCB-method atmosphere, ceramic layer 2 and Copper Foil are heated to the temperature of 400 DEG C-1083 DEG C,

Ceramic layer 2 and Copper Foil are cooled to room temperature, and

Thereby the temperature oxidation ceramic layer 2 at 850 DEG C-1450 DEG C after aforesaid method forms middle layer 3, wherein preferably before described oxidation, remove used Copper Foil.

In Al2O3 middle layer 3 another method of copper doped by the following method step carry out:

With aforesaid method purification pottery or ceramic layer 2,

Thereby form without copper doping the Al2O3 middle layer 3 that still comprises defect sites 7 at the temperature oxidation ceramic layers 2 of 800 DEG C-1450 DEG C,

The Copper Foil of DCB-crimping through being oxidized on middle layer 3,

Remove Copper Foil, for example, remove by chemical milling,

Thereby form middle layer 3 in the temperature of 800 DEG C-1450 DEG C again oxidation ceramic layer 2.

Use above-mentioned two methods in Al2O3 middle layer 3, to embed copper/cupric oxide equally.

Form the not continuous middle layer 3 containing defect sites and interruption by the insert 9 of copper/cupric oxide, as shown in Figure 5.

Based on embodiment, the present invention is described above.Should be understood that a large amount of changes and modification are possible, and do not depart from thus the present invention based on invention theory.

Reference numerals list

1 base material

2 ceramic layers

The 2.1 undressed paper tinsels that formed by ceramic material

2.2 fired former base potteries

3 middle layers

4,5 metallides

4.1 metallic region

6 upper layers

7 defect sites or interruption

8 layers that formed by copper, cupric oxide or cupric ion

9 cupric inserts

Claims

1. for the preparation of the method for DCB-base material, described DCB-base material is provided with at least one ceramic layer (2) being substantially made up of aluminium nitride (AlN) separately, described ceramic layer (2) is at least one face side, preferably in two face side, be provided with the middle layer (3) substantially being formed by aluminum oxide (Al2O3), and be provided with the metallide that at least one is formed by metal level or tinsel on each middle layer (3), wherein form undressed paper tinsel (2.1) by casting and/or rolling and/or suppress by aluminium nitride and sintering aid, and prepare former base ceramic layer (2.2) by sintering by described undressed paper tinsel (2.1), and wherein at least one face side of ceramic layer (2), preferably in two face side, form middle layer (3), then make to be connected with described middle layer (3) through metal level or the tinsel of preoxidation by DCB-crimping,

It is characterized in that,

In the relevant surfaces side of ceramic layer (2), form at least one middle layer (3) before, remove being caused by sintering process of existing in the relevant surfaces side of described ceramic layer (2) and particularly comprise the impurity of sintering process and/or the upper layer of reaction product (6).

2. method according to claim 1, is characterized in that, mechanically except scalping (6), for example, by brushing, polishing, polishing, sandblast, high pressure spraying.

3. method according to claim 1 and 2, is characterized in that, removes scalping (6) by chemical treatment, for example, by with basic solution, be preferably greater than 10 by PH-value, the aqueous solution processing that preferably PH-value is greater than 12.

4. method according to claim 3, is characterized in that, the treatment temp between 20 DEG C and 100 DEG C is preferably removed scalping (6) in the temperature that is greater than 50 DEG C.

5. according to the method described in claim 3 or 4, it is characterized in that, by with soda lye, preferably process with 5% soda lye and/or pass through to process except scalping (6) with potassium hydroxide (KOH) and/or sodium carbonate (Na2CO3).

6. according to the method described in aforementioned claim any one, it is characterized in that, in liquid and/or steam, thereby for example by remove scalping (6) in the Temperature Treatment up to 300 DEG C with hot mode in autoclave under pressure.

7. according to the method described in aforementioned claim any one, it is characterized in that, forming at least one middle layer (3) before, in at least one face side of ceramic layer (2), apply the thin layer that forms or formed by least one other copper-containing compound by copper or cupric oxide, and form at least one middle layer (3) by thermooxidizing afterwards.

8. according to the method described in aforementioned claim any one, it is characterized in that, the so long time is carried out in thermooxidizing, until the layer thickness of at least one middle layer (3) is adjusted between 0.5 μ m and 10 μ m.

9. according to the method described in aforementioned claim any one, it is characterized in that, overlapping or carry out successively in time in time at least in part for removing the machinery of at least one upper layer (6) and chemical process.

10. according to the method described in claim 6-8 any one, it is characterized in that, by ceramic layer being immersed to the aqueous solution of copper ions, for example Cu++ ion content is 0.005 to 2.0Mol/l the aqueous solution, thereby applies the thin layer that is formed or be made up of at least one copper-containing compound by copper or cupric oxide.

11. according to the method described in claim 6-9 any one, it is characterized in that, thereby deposits and/or apply by electroless plating by sputter and/or by CVD-the thin layer forming by copper or by cupric oxide or by least one other copper-containing compound.

12. according to the method described in aforementioned claim any one, it is characterized in that, by thermooxidizing, by in the oxygen-containing atmosphere between 10% and 90%, ceramic layer (2) is heated to the temperature between 800 DEG C and 1450 DEG C in air or in oxygen share, thereby form at least one middle layer (3).

13. according to the method described in aforementioned claim any one, it is characterized in that following method steps:

In at least one face side of the ceramic layer (2) through purifying being formed by AlN, apply the tinsel through oxidation that at least one is made up of copper or copper alloy,

At least one tinsel and ceramic layer (2) are heated to the temperature of 400 DEG C-1083 DEG C,

Remove at least one tinsel, preferably remove afterwards at cool metal paper tinsel and ceramic layer (2),

The temperature of 850 DEG C-1450 DEG C in oxygen-containing atmosphere oxidation ceramic layer (2) thus at least one face side of ceramic layer (2), form middle layer (3), and

At least one tinsel of DCB-crimping at least one face side of ceramic layer (2).

14. according to the method described in aforementioned claim any one, it is characterized in that following method steps:

The ceramic layer (2) through purifying being formed by AlN the temperature oxidation of 800 DEG C-1450 DEG C,

At least one tinsel being formed by copper or copper alloy of DCB-crimping at least one face side of the ceramic layer (2) through oxidation,

Remove at least one tinsel, preferably remove by etching,